K-4391 is a designation for a specific type of military equipment, often associated with naval or defense systems. It may refer to a particular model or version of a submarine, ship, or other military vehicle, depending on the context. The designation helps in identifying and categorizing various military assets for operational purposes. In military nomenclature, the "K" prefix typically indicates a connection to naval forces, while the numbers that follow can signify the model or series. Understanding such designations is crucial for military logistics, planning, and communication among personnel involved in defense operations.